The register's side of signing in with an address, a password that never
leaves the device (SRP-6a) and a code from an authenticator (ADR 0017),
with members forwarding every step through AccountRegister:
- password.set: salt, Argon2id's costs, SRP's verifier, the public keys
and the private keys wrapped twice, all made on the device; with the
address a mailed code proves, an anonymous person becomes identified
under their ID. It signs in once an authenticator is confirmed.
- passwordSignIn.begin and complete: SRP's two steps with a TOTP or
recovery code. An address nobody has is answered from a decoy key as
an account would be; every wrong credential is refused alike.
- authenticator: secrets sealed under totpKey (XChaCha20-Poly1305, bound
to their row), each code accepted once, ten recovery codes with the
first, the last one kept.
- accountRecovery: a lost authenticator reset 72 hours after the
password and a mailed code or the recovery phrase ask, a lost password
set anew with the phrase's signature, or the account reset with new
keys 72 hours after a mailed code asks; a mail at each start, a
sign-in calling it off.
- An account with a password no longer signs in by a mailed code or
GitHub; no new GitHub account is linked where passwords are offered,
and from GITHUB_SIGN_IN_ENDS GitHub signs nobody in and its IDs go.
Five tables, added by the module's migration; deletePerson deletes
their rows.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
A code holds 40 bits, which plain SHA-256 hashes in a leaked database
would give up to guessing; HMAC-SHA256 under a key of the instance kept
outside the database (recoveryCodeKey, at least 32 characters) gives
nothing to guess against without it. Decided 20 Oct 2026.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
ADR 0017's second factor, in halkyon_base_server (base.dart):
- RFC 6238 with HMAC-SHA1, 6 digits, 30-second steps, one step either
way. checkTotp takes the account's last accepted step as a required
argument and refuses a code of that step or before, so no code is
accepted twice; every step of the window is computed and compared.
- 160-bit secrets in RFC 4648 Base32 (strict decoding); the otpauth
URI with issuer and account escaped.
- Ten recovery codes of eight Crockford characters (short_code.dart),
kept as SHA-256 hashes, each used once, every hash compared in
constant time.
- Tests: RFC 6238 Appendix B (8 digits, SHA-1, SHA-256, SHA-512), the
window, replay, RFC 4648's Base32 vectors, the recovery codes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
ADR 0017's step 1. Generic over group and hash (SrpGroup); production
takes RFC 5054's 3072-bit group with SHA-256. k = H(N | PAD(g)),
u = H(PAD(A) | PAD(B)), K = H(PAD(S)),
M1 = H(H(N) xor H(g) | H(I) | s | PAD(A) | PAD(B) | K),
M2 = H(PAD(A) | M1 | K). A and B must lie in 1..N-1 and u must not be
0; a and b are 256 bits from Random.secure(); proofs are compared in
constant time. x comes from the caller (halkyon_keys makes it); RFC
5054's own x is there for the vectors only.
- The register's half in halkyon_base_server (base.dart: srpChallenge,
srpVerify), the device's written by hand in halkyon_base_client
(srp.dart: SrpClient, srpVerifier). Serverpod's generator cleans and
writes only a client's lib/src/protocol/ (serverpod_cli 4.0.4's
_getDirectoriesRequiringCleaning; a generate leaves srp/ untouched).
- Tests: RFC 5054 Appendix B on both halves; the client against the
register, succeeding and every refusal.
- The module's tests depend on its client, and pub resolves every
member's dev dependencies, so Learn's server image takes the module's
client into its workspace too.
- The format check covers the hand-written half.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
halkyon_base runs as the instance's register or as one of its members.
The register keeps the ways in, handles and profiles; members ask it
over HTTP with the instance's shared secret (instanceSecret), and open
sessions of their own for its accounts, under the same account ID.
- AccountsMode from the environment: INSTANCE_MEMBERS on the register,
ACCOUNT_REGISTER_URL on a member. Learn always holds the register
(Explore joins the profiles); Todo is a member where it is set.
- AccountRegister: LocalRegister, RemoteRegister, an in-memory one in
tests. Calls between services on the web server, refused without the
secret (constant-time compare); a server needing it doesn't start
without it.
- Deleting an account deletes it everywhere: notices per member kept in
the deletion's transaction (account_deletion_notice), told at once and
hourly until confirmed; members prune daily whom the register no longer
knows, never while it knows none of them or can't be reached.
- Deploy: INSTANCE_SECRET and INSTANCE_MEMBERS in compose and .env.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
People's public profiles are the instance's register's (ADR 0016), so
the module now holds them: the public_profile table (unchanged, so
Learn's migration records versions only; devices get the table empty,
as they hold every module's tables), the profile and profiles
endpoints under `base`, the handle rules, the link checks and the page
at /@handle, whose foot names the app as the host's configuration says
(profilePageNote). Deleting a person deletes their profile in the
module's core.
Hosts read profiles through the module (profileOf, profilesOf,
personWithHandle, fixHandle; saveProfile for their tests), behind an
AccountRegister that is this server's own database for now. Learn's
feedback, discussions and publishing ask it; publishing fixes the
handle just before it writes the release, outside its transaction.
Explore still joins the table in its search, so Learn holds the
register wherever it runs. Learn's app calls the module's endpoints;
a profile not found is ProfileNotFoundException. Todo's database gets
the table too (it was never deployed).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
An operator's DATA_LOCATION and BACKUP_LOCATION may name a subdivision
(ISO 3166-2, US-CA, DE-BY) besides the EU or a country. The app adds
"(EU)" to a member country and the country to a subdivision ("Germany
(EU)", "California, United States", "Bavaria, Germany (EU)"), in
English and German, and shows the most specific flag there is: a
subdivision's own where the flag package has one, else its country's.
Subdivision names come from Unicode CLDR 48.2 (tool/subdivision_names.py),
bundled with their licence, which the app registers.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
What every Halkyon app's shell needs, taken from Halkyon Learn's and set
on halkyon_base's client: the instances a device keeps an account on,
the first start's tiles and where an instance keeps people's data, the
account switcher; signing in anonymously, with GitHub or an email code,
switching person and the start screen; the gates that build an app's
dependencies per instance and per person; and the sync service with its
status, Settings card and banner. Texts of its own in English and
German take the app's name; what only the app can say, it passes in.
Fakes for apps' tests are in testing.dart.
An instance's basics now name the app it serves (`app`, set by the
host's configuration), and an app accepts only an instance of its own.
SerialQueue and CoalescingRunner move into halkyon_core.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
What every Halkyon server has, taken from Halkyon Learn's: anonymous,
GitHub and email-code sign-in with their endpoints, an account's ways
in and its deletion, the pruning of abandoned anonymous people, of
sign-up attempts and of expired codes, and the instance's basics (the
sign-in ways offered, the source link, the minimum app build, where
people's data and its backups are). Endpoints sit under the nickname
`base`. A host configures it in one place before its pod starts: its
name for the mails, its source link, its minimum build, and hooks that
delete its own data with a person.
The tables keep Learn's names, columns and indexes, so a host moving
onto the module migrates nothing but version rows. Server package under
the SSPL, client under the AGPL, as Learn's are.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>
